A FinFET is a field effect transistor that often includes an active region of a semiconductor material protruding from a substrate, resembling a fin. The fin usually includes a source region and a drain region, with areas of the fin separated by shallow trench isolation (STI). A FinFET also includes a gate region located between the source region and the drain region. The gate region is usually formed on a top surface and side surfaces of the fin so as to wrap around the fin. A channel region within the fin often extends under the gate region between the source region and the drain region. Compared to planar devices, FinFETs usually have better short channel effects (SCE) to enable continuous scaling, and have larger channel widths to yield higher driving currents.